No, it's nothing you're doing wrong paulified but the puzzle has been posted as a plain diagram, without any moves included in it ! If you click on FEN/PGN, all you see is the single line FEN string which only gives the position.

It's frustrating when people do that because you can sit there for some time making pointless moves, none of which are accepted. The thing that tells you something's wrong is that there's no 'Incorrect Move' message.

This is how the puzzle should look with what I think is the correct solution (the moves list gives alternative lines)....

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